MTFCA Forum

Hello T people

I have wear in the bore of the camshaft bearing block. I have about 0.01 inch play. What is the best thing I can do to fix the problem?

Greetings Beat

Vonau, do you have the same or similar measurement when the camshaft is in the bearing?

Yes, the dimensions are the same as with the crankshaft. You can also see signs of wear on the block, so new bearings won't fix the problem.
The bearings are close to the crankshaft. I actually expected that to be the problem.

Greetings Beat

At one time oversized O.D. bearings were made. But, no more. But maybe you can find someone who has one to sell you.
Dan

P.S. It would not take much to make them again. I think there would be a market. I am finding more blocks this way too.

I have two thoughts:

One idea is to punch the surfaces with a punch so the bearing is tight and mount with Loctite so the gaps are filled and glued.

Another idea would be to mount an insert plate. But I still don't know how I should do it and bring it in.

But neither option makes me happy. Therefore the question of possibilities what others have done.


I would like to build this engine without high costs in order to put my touring into operation for the time being. This block is not worth doing a complete overhaul because of oversize pistons, valves, etc.
It's supposed to give me time to cleanly build another engine. However, the second block shows the same problem, although not to the same extent.

Beat

I think that right now .004" (.10mm) shim stock is your friend. Wrap the bearing, install, capture with securing bolt.

... as Scott suggests, and I would not use the Loc-Tite that you mentioned.

I've knurled bearing shells on a lathe using a 3/4" bar to keep the shells from distorting. I tried shim stock but the gap was too small.

Just spitballing here but could you drill & tap both sides of the boss, then set the bearing with long torque or Allen screws. If the clearance is so small that shims wouldn’t work. I realize it could alter the cam running true but as stated thinking outside the box & thinking out loud, might better shut up now. Now boys & girls no haters, I’m sensitive.

You're a good man Charlie Brown ( JJT) Lol

Have you looked at shaft repair sleeves to take up the space? https://www.mcmaster.com/products/shaft-repair-sleeves/

As John pointed out this may change how true the cam runs but I have made tapered allen bolts to take up cam end play and if you make it a bit to long it will push the cam to one side of the bore, which will also change your timing gear back lash (with the worn cam bore it is most likely excessive). I have included a picture of what I start with and what I end up with. Good luck. Dennis

Lewis Rector did much the same to eliminate bearing shell movement in the block. He made tapered cam set screws for the first and second bearings so they entered the alignment holes and pressed against the bearing shells to hold them tight. I never tried it myself.